Effect of Pilot Injection on Mixture Formation, Ignition Process and Flame Development in Diesel Combustion

2013 ◽  
Vol 390 ◽  
pp. 327-332 ◽  
Author(s):  
Amir Khalid ◽  
M. Jaat ◽  
Izzuddin Zaman ◽  
B. Manshoor ◽  
Mas Fawzi
Keyword(s):  
Ignition Delay ◽  
High Speed ◽  
Combustion Process ◽  
Video Camera ◽  
Delay Period ◽  
Ignition Process ◽  
Pilot Injection ◽  
Mixture Formation ◽  
Digital Video Camera ◽  
Ignition Delay Period

The alternative combustion strategies with systematic control of mixture formation have provided new opportunities and considerable improvement in the combustion process and response to meet the stringent emissions standards. Purpose of this research is to investigate the influences of pilot injection on the fuel-air premixing especially during ignition delay period. During this period, the interaction between fuel spray and surrounding gas prior to ignition which linked to the improvement of mixture formation, ignition process and initial heat recovery thus predominantly influences the combustion process and exhaust emissions. This study investigates the effects of pilot injection using a rapid compression machine together with the schlieren photography and direct photography methods. The detail behavior of mixture formation during ignition delay period was investigated using the schlieren photography system with a high speed digital video camera. This method can capture spray evaporation, spray interference and mixture formation clearly with real images. Ignition process and flame development were investigated by direct photography method using a light sensitive high-speed color digital video camera. Pilot injection promotes mixture formation during ignition delay period and slower oxidation reaction and thus leads to earlier rise and lower peak heat release rate.

Effect of High Swirl Velocity on Mixture Formation and Combustion Process of Diesel Spray

2012 ◽  
Vol 229-231 ◽  
pp. 695-699 ◽  
Author(s):  
Amir Khalid ◽  
Bukhari Manshoor
Keyword(s):  
Combustion Chamber ◽  
High Speed ◽  
Combustion Process ◽  
Video Camera ◽  
Exhaust Emissions ◽  
Ignition Process ◽  
Mixture Formation ◽  
Digital Video Camera ◽  
Swirl Velocity ◽  
Flame Development

Diesel engines generate undesirable exhaust emissions during combustion process and identified as major source pollution in the worldwide ecosystem. To reduce emissions, the improvements throughout the premixing of fuel and air have been considered especially at early stage of ignition process. Purpose of this study is to clarify the effects of swirl velocity on flow fuel-air premixing mechanism and burning process in diesel combustion that strongly affects the exhaust emissions. The effects of physical factors on mixture formation and combustion process to improve exhaust emissions are discussed in detail. This study investigated diesel combustion fundamentally using a rapid compression machine (RCM) together with the schlieren photography and direct photography methods. RCM was used to simulate actual phenomenon inside the combustion chamber with changing design parameter such as swirl velocity, injection strategies and variable nozzle concept. The detail behavior of mixture formation during ignition delay period was investigated using the schlieren photography system with a high speed digital video camera. This method can capture spray evaporation, spray interference and mixture formation clearly with real images. Ignition process and flame development were investigated by direct photography method using a light sensitive high-speed color digital video camera. Moreover, the mechanism and behavior of mixture formation were analyzed by newly developed image analysis technique. Under high swirl condition, the ignition delay is extended, the higher heat losses and unutilized high-density oxygen associated with slower initial heat recovery begins might be the explanation for the longer combustion duration, reductions of pick heat release and promote combustion and soot oxidation. The real images of mixture formation and flame development reveal that the spray tip penetration is bended by the high swirl motion, fuel is mainly distributed at the center of combustion chamber, resulting that flame is only formed at the center region of the combustion chamber. It is necessary for high swirl condition to improve fuel-air premixing.

Effect of Inlet Air Temperature on Auto-Ignition of Fuels With Different Cetane Number and Volatility

2011 ◽  
Author(s):  
Chandrasekharan Jayakumar ◽  
Ziliang Zheng ◽  
Umashankar M. Joshi ◽  
Walter Bryzik ◽  
Naeim A. Henein ◽  
...  
Keyword(s):  
Air Temperature ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Cetane Number ◽  
Delay Period ◽  
Inlet Temperature ◽  
Ignition Process ◽  
Ultra Low Sulfur Diesel ◽  
Auto Ignition ◽  
Ignition Delay Period

This paper investigates the effect of air inlet temperature on the auto-ignition of fuels that have different CN and volatility in a single cylinder diesel engine. The inlet air temperature is varied over a range of 30°C to 110°C. The fuels used are ultra-low-sulfur-diesel (ULSD), JP-8 (two blends with CN 44.1 & 31) and F-T SPK. Detailed analysis is made of the rate of heat release during the ignition delay period, to determine the effect of fuel volatility and CN on the auto-ignition process. A STAR-CD CFD model is applied to simulate the spray behavior and gain more insight into the processes that immediately follow the fuel injection including evaporation, start of exothermic reactions and the early stages of combustion. The mole fractions of different species are determined during the ignition delay period and their contribution in the auto-ignition process is examined. Arrhenius plots are developed to calculate the global activation energy for the auto-ignition reactions of these fuels. Correlations are developed for the ID and the mean air temperature and pressure.

scholarly journals Experimental Study of the Effect of Intake Oxygen Concentration on Engine Combustion Process and Hydrocarbon Emissions with N-Butanol-Diesel Blended Fuel

Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1310 ◽  
Author(s):  
Wei Tian ◽  
Yunlu Chu ◽  
Zhiqiang Han ◽  
Xiang Wang ◽  
Wenbin Yu ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Ignition Delay ◽  
Cetane Number ◽  
Combustion Process ◽  
Delay Period ◽  
Blended Fuel ◽  
The Difference ◽  
Hc Emissions ◽  
Oxygen Medium ◽  
Ignition Delay Period

This paper summarizes a study based on a modified, light, single-cylinder diesel engine and the effects of the physicochemical properties for n-butanol-diesel blended fuel on the combustion process and hydrocarbon (HC) emissions in the intake at a medium speed and moderate load in, an oxygen-rich environment (Coxy = 20.9–16%), an oxygen-medium environment (Coxy = 16–12%), and an oxygen-poor environment (Coxy = 12–9%). The results show that the ignition delay period is the main factor affecting the combustion process and it has a decisive influence on HC emissions. In an oxygen-medium environment, combustion duration affected by the cetane number is the main reason for the difference in HC emissions between neat diesel fuel (B00) and diesel/n-butanol blended fuel (B20), and its influence increases as the intake oxygen concentration decreases. In an oxygen-poor environment, in-cylinder combustion temperature affected by the latent heat of vaporization is the main reason for the difference in HC emissions between B00 and B20 fuels, and its influence increases as the intake oxygen concentration decreases. By comparing B20 fuel with diesel/n-butanol/2-ethylhexyl nitrate blended fuel (B20 + EHN), the difference in the ignition delay period caused by the difference in the cetane number is the main reason for the difference in HC emissions between B20 and B20 + EHN fuels in oxygen-poor environment, and the effect of this influencing factor gradually increases as the intake oxygen concentration decreases.

Experimental Investigation of Mixture Formation and Flame Development Using the Basics Technique of Schlieren Optical Visualization Principle

2014 ◽  
Vol 660 ◽  
pp. 474-478
Author(s):  
Dahrum Samsudin ◽  
Safwan Othman ◽  
M.D. Anuar ◽  
Bukhari Manshoor ◽  
Amir Khalid
Keyword(s):  
Low Cost ◽  
Combustion Process ◽  
Video Camera ◽  
Combustible Mixture ◽  
Biodiesel Fuel ◽  
Mixture Formation ◽  
Digital Video Camera ◽  
Optical Visualization ◽  
Flame Development ◽  
Air Mixing

The Schlieren technique remains to be one of the most powerful technique to visualize the flow and it is relatively easy to implement, high and variable sensitivity, low cost and its used conventional of light. This technique allows us to see the invisible of the optical inhomogeneities in transparent media like air, water and glass that otherwise cause only ghostly distortions of our normal vision. This research investigates the mixture formation and flame development of biodiesel fuel using the Schlieren optical visualization principle. This method can capture spray evaporation, spray interference, mixture formation and flame pattern clearly with real images. During the experiment, the camera lens was used with telephoto lenses (Nikon 70-300mm f/4-5.6G) in order to capture a large amount of light especially the low flame intensity during the initial flame development. The flame development was captured with color images from a color digital video camera. This method can capture the flow of fluids of varying density, such as spray evaporation, spray interference and mixture formation clearly with real images. The result shows that the mechanism of fuel-air mixing and a better comprehension of combustible mixture that can give valuable information to improve and optimize the combustion process.

scholarly journals Study on Diesel Low-Nitrogen or Nitrogen-Free Combustion Performance in Constant Volume Combustion Vessels and Contributory

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 923
Author(s):  
Qinming Tan ◽  
Yihuai Hu ◽  
Zhiwen Tan
Keyword(s):  
Ignition Delay ◽  
High Speed ◽  
Delay Period ◽  
Constant Volume ◽  
Combustion Performance ◽  
Combustion Flame ◽  
O2 Concentration ◽  
Constant Volume Combustion ◽  
Low Nitrogen ◽  
Ignition Delay Period

This paper studies the combustion performance of diesel in constant volume combustion vessels under different conditions of mixed low-nitrogen (O2 and N2) or non-nitrogen (O2 and CO2) in varying proportions. The high-speed camera is used to shoot the combustion flame in the constant volume combustion vessel. The process and morphology of the combustion flame are amplified in both time and space to study and analyze the effects of different compositions and concentrations in gases on the combustion performance of diesel and conduct a study on the contributory factors in the performance of diesel with no nitrogen. According to the study, in the condition of low nitrogen, the O2 concentration is more than 60%, the ignition delay period is shortened, the combustion flame is bright and slender, it spreads quickly, and the blue flame appears when the O2 concentration reaches 70%; While for nitrogen-free combustion, only when the O2 concentration reaches 30% is the combustion close to the air condition; when the O2 concentration reaches 40%, the combustion condition is optimized obviously and the combustion flame is relatively slender compared to the air working condition. Similarly, with the increase of the O2 concentration, the ignition delay period of nitrogen-free diesel is shortened, the duration is extended, and the combustion performance is optimized. In addition, when the O2 concentration reaches 50%, with the decrease of the initial temperature, the ignition delay period is prolonged, and the duration is shortened obviously. When the temperature is lower than 700 K, there is no ignition. The increase of the diesel injection pressure is beneficial to optimize the ignition performance of diesel non-nitrogen combustion and shorten its ignition delay period and combustion duration. Related research has important guiding significance to optimize nitrogen-free combustion technology, which produces no NOx of the diesel engine.

Experimental investigations to predict optimistic biodiesel(s) and its optimistic operating conditions by varying ignition delay period and fuel spray pressures for lower emissions and better performance

2020 ◽  
Vol 234 (19) ◽  
pp. 3890-3902
Author(s):  
Vishal V Patil ◽  
Ranjit S Patil
Keyword(s):  
Methyl Ester ◽  
Ignition Delay ◽  
Seed Oil ◽  
Delay Period ◽  
Operating Conditions ◽  
Experimental Investigations ◽  
Rubber Seed Oil ◽  
Rubber Seed ◽  
Neem Seed Oil ◽  
Ignition Delay Period

In this study, different characteristics of sustainable renewable biodiesels (those have a high potential of their production worldwide and in India) were compared with the characteristics of neat diesel to determine optimistic biodiesel for the diesel engine at 250 bar spray pressure. Optimistic fuel gives a comparatively lower level of emissions and better performance than other selected fuels in the study. Rubber seed oil methyl ester was investigated as an optimistic fuel among the other selected fuels such as sunflower oil methyl ester, neem seed oil methyl ester, and neat diesel. To enhance the performance characteristics and to further decrease the level of emission characteristics of fuel ROME, further experiments were conducted at higher spray (injection) pressures of 500 bar, 625 bar, and 750 bar with varying ignition delay period via varying its spray timings such as 8°, 13°, 18°, 23°, 28°, and 33° before top dead center. Spray pressure 250 bar at 23° before top dead center was investigated as an optimistic operating condition where fuel rubber seed oil methyl ester gives negligible hydrocarbon emissions (0.019 g/kW h) while its nitrogen oxide (NOX) emissions were about 70% lesser than those observed with neat diesel, respectively.

Review of the Investigation of Fuel-Air Premixing and Combustion Process Using Rapid Compression Machine and Direct Visualization System

2013 ◽  
Vol 465-466 ◽  
pp. 265-269 ◽  
Author(s):  
Mohamad Jaat ◽  
Amir Khalid ◽  
Bukhari Manshoor ◽  
Siti Mariam Basharie ◽  
Him Ramsy
Keyword(s):  
High Speed ◽  
Combustion Engine ◽  
Early Stage ◽  
Combustion Process ◽  
Injection Pressure ◽  
Rapid Compression Machine ◽  
Mixture Formation ◽  
Visualization System ◽  
Optical Visualization ◽  
Rapid Compression

s :This paper reviews of some applications of optical visualization system to compute the fuel-air mixing process during early stage of mixture formation and late injection in Diesel Combustion Engine. This review has shown that the mixture formation is controlled by the characteristics of the injection systems, the nature of the air swirl and turbulence in thecylinder, and spray characteristics. Few experimental works have been investigated and found that the effects of injection pressure and swirl ratio have a great effect on the mixture formation then affects to the flame development and combustion characteristics.This paper presents the significance of spray and combustion study with optical techniques access rapid compression machine that have been reported by previous researchers. Experimental results are presentedin order to provide in depth knowledge as assistance to readers interested in this research area. Analysis of flame motion and flame intensity in the combustion chamber was performed using high speed direct photographs and image analysis technique. The application of these methods to the investigation of diesel sprays highlights mechanisms which provide a better understanding of spray and combustion characteristics.

scholarly journals MODELING OF IGNITION DELAY PERIOD IN DIESEL ENGINE

2019 ◽  
Vol 0 (1) ◽  
pp. 34-38
Author(s):  
А. П. Марченко ◽  
І. В. Парсаданов ◽  
А. В. Савченко
Keyword(s):  
Diesel Engine ◽  
Ignition Delay ◽  
Delay Period ◽  
Ignition Delay Period
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